Shirley Mark, Howlett Sally, Port Gordon
School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
Department of Biology, University of York, Heslington, York YO10 5DD, UK.
Insects. 2020 Oct 29;11(11):742. doi: 10.3390/insects11110742.
Models to forecast slug populations make assumptions about growth and mortality in response to environmental factors. To refine these models, the growth trajectories and survival of , a worldwide pest, hatching in spring and autumn were compared at three rearing temperatures (ambient, 12 °C and 15 °C). reared under identical conditions showed great variation in growth and strong bimodality in growth rates. At all rearing temperatures, growth was influenced by hatching season; in all cases, fast growers dominated in autumn and slow growers dominated in spring. Survival was influenced by hatching season: autumn-born slugs survived better at ambient temperatures, but spring-born slugs had better survival at 15 °C. may be partitioned into "slow growers" and "fast growers". Fast growers responded to warmer conditions, growing to large sizes. Slow growers, in contrast, gained weight at comparable rates to ambient reared slugs, regardless of the elevated constant temperatures. The peaks of slug activity in autumn and spring are possibly not distinct generations as some slugs may mature early/late and slip into the alternative cohort. Rather, the observed autumn and spring peaks in slug numbers may be a response of a mixed-age population to the favourable environmental conditions at that time.
预测蛞蝓种群数量的模型对蛞蝓在环境因素影响下的生长和死亡率做出了假设。为了优化这些模型，在三种饲养温度（环境温度、12℃和15℃）下，比较了一种世界性害虫蛞蝓在春季和秋季孵化后的生长轨迹和存活率。在相同条件下饲养的蛞蝓在生长方面表现出很大差异，生长速率呈现出明显的双峰性。在所有饲养温度下，生长都受孵化季节的影响；在所有情况下，秋季孵化的蛞蝓生长速度快的占主导，而春季孵化的蛞蝓生长速度慢的占主导。存活率也受孵化季节的影响：秋季出生的蛞蝓在环境温度下存活率更高，而春季出生的蛞蝓在15℃时存活率更高。蛞蝓可分为“生长缓慢型”和“生长快速型”。生长快速型对温暖环境有反应，能长到较大体型。相比之下，生长缓慢型蛞蝓无论恒温是否升高，体重增加速度与在环境温度下饲养的蛞蝓相当。秋季和春季蛞蝓活动的高峰期可能并非不同世代，因为一些蛞蝓可能早熟/晚熟并混入另一个群体。相反，观察到的秋季和春季蛞蝓数量高峰可能是一个混合年龄种群对当时有利环境条件的反应。
